Three-dimensional reconstruction of F-actin, thin filaments and decorated thin filaments.

摘要: Abstract The characteristic “arrowheads” appearance seen in electron micrographs of negatively-stained F-actin filaments when “decorated” with myosin or heavy meromyosin, has shown the structural polarity actin, but it was not possible previously to deduce from such images detailed way which individual units were attached G-actin molecules, Using highly purified preparations subfragment 1 (the “head” subunit) and improvements negative staining technique, we able obtain much better decorated filaments. These images, together ones untreated have been analysed by three-dimensional reconstruction technique DeRosier & Klug (1968), low resolution models calculated structures built. show that one molecule attaches each double-helical structure. appear somewhat elongated curved, are actin filament a configuration they both tilted slewed respect axis. It is this shape distinctive mode attachment gives their very appearance. This probably present cross-bridges thin at some point cycle action during contraction.